4th Amendment Search and Seizure Protections

The rule of exigent circumstances also applies when suspects attempt to flee from law enforcement. Suppose a suspect runs from the police. Police immediately chase the suspect. 

The Fourth Amendment to the United States Constitution protects personal privacy. It states that every person has a right to be free from unreasonable government intrusion into their persons, homes, businesses, and property.

Lawmakers and the courts have put legal safeguards in place to ensure that law enforcement officers only interfere with individuals' Fourth Amendment rights under limited circumstances and through specific methods.

This article discusses when the Fourth Amendment applies, what it means for warrants and searches conducted by law enforcement, and how to protect your rights.

What Does the Fourth Amendment Protect?

In the realm of criminal law, the Fourth Amendment to the U.S. Constitution's "search and seizure" protections extend to the following:

  • A law enforcement officer's physical apprehension or "seizure" of a person by way of a stop or arrest
  • Police searches of places where an individual has a legitimate expectation of privacy

The Fourth Amendment provides safeguards during searches and detentions. It also prevents unlawfully seized items from being used as evidence against them in criminal cases. The degree of protection available in a particular case depends on the following:

  • The nature of the detention or arrest
  • The characteristics of the place searched
  • The circumstances under which the search takes place

Generally, the government must obtain a valid search warrant to search your person or property. If a police officer performs a warrantless search of your home, it will likely be an illegal search. While there are exceptions to the general rule, a warrantless search is often unlawful. The warrant requirement protects citizens from unreasonable searches and preserves the rights guaranteed to them by the U.S. Constitution.

When Does the Fourth Amendment Apply?

The Fourth Amendment provides constitutional protection to individuals in many different situations, such as:

  • An individual is stopped for police questioning while walking down the street
  • Police pulling over a motorist for a minor traffic infraction, and the police officer searches the vehicle's trunk
  • Police arresting an individual
  • Police officers entering an individual's house to arrest them
  • Police officers entering an individual's apartment to search for evidence of a crime
  • Police officers entering a business to search for evidence of a crime

These are just a few examples of situations where Fourth Amendment rights arise. In most instances, a police officer may not search or seize an individual or their property unless the officer has at least one of the following:

  • A belief rising to the level of "probable cause" that an individual has committed a crime

The Fourth Amendment rules regarding police searches of vehicles are complicated. Consider contacting a criminal defense lawyer if you have questions regarding a search.

Probable Cause

Police officers, in most cases, must apply for a search warrant before searching. This requires them to provide an affidavit and appear before a neutral judge or magistrate. The police officer must show they have probable cause for conducting a search.

To establish probable cause, the officer must show the following:

  • The police officer is aware of certain facts and circumstances
  • These facts and circumstances are from a reasonably trustworthy source
  • A reasonable person would believe that a criminal offense has been committed or is about to occur

The judge or magistrate will either issue or deny the warrant. The warrant must specifically lay out where and what police can search. For example, it may limit the search to a specific area of a house.

When Does the Fourth Amendment Not Apply?

Your Fourth Amendment constitutional rights protect you from unreasonable searches and seizures. However, the Supreme Court has ruled that some circumstances permit the government to perform warrantless searches. Some exceptions to the general warrant requirement include the following:

Search Incident to Arrest

Police do not require a warrant to search a person following a lawful arrest. Following an arrest, the Fourth Amendment allows officers to search the arrestee's person, clothing, and areas within the arrestee's immediate vicinity (usually within the person's reach).

Exigent Circumstances

Certain emergencies allow law enforcement to perform a warrantless search, seizure, or arrest. Such circumstances are referred to as exigent circumstances.

For example, if the police officer has a reasonable belief that a suspect will destroy evidence, they may perform a warrantless search. A judge will determine after the arrest whether the circumstances justified the officer's actions.

The chase starts in a public place, and the suspect eventually runs into their private residence. Because the police are in "hot pursuit," they likely do not need a warrant to enter the residence. The U.S. Supreme Court addressed this issue in Warden v. Hayden (1967).

Additionally, a warrantless search or arrest is likely justified if the officer reasonably believes the suspect will cause bodily harm to another person.

Stop and Frisk

If an officer reasonably suspects that criminal activity is being or will be committed in public, the Fourth Amendment allows them to stop the person. The officer can then perform a limited search of the suspect's clothing.

Such a search is known as a stop and frisk or a Terry Stop. The term "Terry Stop" comes from the 1968 U.S. Supreme Court case Terry v. Ohio.

The limited search allows an officer to pat down the suspect's outer clothing to ensure they are unarmed. If a police officer finds contraband such as illegal drugs or drug paraphernalia, the officer cannot seize these. Police can only seize weapons during the stop and frisk.

If an officer stops you in this way, they may ask you for identification. But you are not required to provide it. However, keep in mind that refusing to identify yourself can provide probable cause for the officer to arrest you.

Roadside Checkpoints

Certain roadside checkpoints are allowed under the Fourth Amendment. Law enforcement must design these roadside checkpoints to address specific problems that they cannot address through traditional means.

For example, the Supreme Court has held that brief warrantless seizures at checkpoints that identify drunk drivers and illegal aliens are lawful. Such stops relate to keeping roadways safe and the borders secure, respectively.

However, the Supreme Court has ruled that if a checkpoint's primary purpose is to detect ordinary criminal activity, the checkpoint violates the Fourth Amendment. In the case of City of Indianapolis v. Edmond, the city of Indianapolis set up roadside checkpoints to intercept unlawful drugs. Because the checkpoint's primary purpose was to detect ordinary criminal activity, it was deemed unlawful.

Traffic Stops

Police do not need probable cause to stop a vehicle. Instead, they only need a reasonable suspicion.

A reasonable suspicion refers to whether a reasonable person would believe criminal activity was occurring. To have a reasonable suspicion, police must act on specific facts and inferences. For instance, if a car's taillight is out or the driver is speeding, the police have a reasonable suspicion to stop the vehicle because those two things are against the law.

If the officer develops probable cause after the driver pulls over, the officer can search the vehicle's interior. Depending on what probable cause the officer has developed, they may be able to search the vehicle's trunk. Otherwise, they may only have probable cause to search the area immediately around the driver.

If the police pull over a vehicle and see contraband in plain view, they can seize it. For example, if police see contraband in the back seat of a car, they can seize it. Additionally, such a seizure likely justifies probable cause for the officer to search the vehicle and the driver.

Good Faith

Suppose a police officer performs a search based on a warrant. After police complete the search, a court determines the warrant is defective. A warrant may be defective for failing to meet the warrant requirements explained above. If a warrant is deemed invalid, the court will typically exclude any seized evidence from the criminal case.

But, the U.S. Supreme Court has ruled that a search performed with an invalid warrant may still be considered reasonable. If a judge issued the warrant, and the warrant's defect did not result from willful police deception, the search may be considered lawful. This is known as the good faith exception. It protects police officers who acted in good faith based on what they believed was a valid warrant.


If a police officer asks to search your vehicle, you can deny or consent to their request. If you agree, you have consented to the search. If you voluntarily consent to a search, police do not need to obtain a warrant. Instead, they can legally search your vehicle because you said they could. Your voluntary consent has eliminated your reasonable expectation of privacy in your car. Therefore, the search does not violate your Fourth Amendment protections.

However, coerced consent has been an issue in many cases. As noted above, the government requires probable cause to believe a search will yield evidence of a crime. With a consent search, police do not need probable cause. In other words, they do not need to show the search will further a criminal investigation.

As prominent law professor Professor Sherry F. Colb noted, “A person's consent to invade his privacy accordingly means that the police do not need a good reason for the invasion. It does not mean that the police have a good reason for it."

What if My Fourth Amendment Rights Are Violated?

If the court finds that a search was conducted in violation of the Fourth Amendment, it will exclude any evidence found from the suspect's criminal case.

The exclusionary rule states that the courts will exclude or prevent evidence obtained from an unreasonable search and seizure from a criminal defendant's trial. For example, consider the following scenarios:

  • An officer arrests someone even though the officer does not have probable cause. The arrest violates the arrestee's individual rights. The court will exclude from the arrestee's criminal case any evidence obtained through the unlawful arrest, such as a confession.
  • Police officers search a suspect's home without obtaining a search warrant. No special circumstances allowed the police to search the house without a warrant. The police seize illegal drugs and weapons during the search. The search violates the suspect's constitutional rights. The court will exclude the seized evidence from the suspect's criminal trial.

Additionally, the court will exclude any evidence derived from an unlawful search. The "fruit of the poisonous tree" doctrine prevents courts from admitting such evidence.

Suppose a police officer performs an unlawful search of a suspect's apartment. In the apartment, the police officer seizes the suspect's diary. Inside the diary, the officer finds a map showing the location of illegal drugs. The officer visits the location and seizes the drugs.

The court will prevent the prosecution from introducing the drugs as evidence at the suspect's criminal trial due to the "fruit of the poisonous tree" doctrine. Because the officer would not have known of the map had they not illegally searched the suspect's apartment, the drugs cannot be introduced as evidence.


The Fourth Amendment guarantees rights that are personal to an individual. Therefore, to have standing, the individual must have a personal right to privacy with regard to the government's search. They cannot assert their personal right on behalf of someone else.

For example, if the police search your private property without a valid warrant—or an exception to the warrant requirement—you have standing to challenge the search. If, instead, the police search your neighbor's house, you do not have standing to challenge the search. You personally do not have a reasonable expectation of privacy in your neighbor's house.

Learn More About Search and Seizure and the Fourth Amendment from a Lawyer

The rules of search and seizure are notoriously complicated. These complex rules mean that a criminal defense attorney can often find problems with government searches. An attorney can provide you with legal counsel regarding the following:

  • Criminal cases in state courts
  • Federal law regarding Fourth Amendment searches
  • Searches involving private property, including cell phones

Contact an experienced criminal defense attorney who can review the search and seizure procedures to see if the government violated your Fourth Amendment rights.

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